Most significant biological phenomena, such as signaling and energy production in living organisms, are caused by the ion concentration difference between the inside and the outside of cells. Representative examples of photosensitive proteins performing these actions are photosystem II and rhodopsin proteins. The photosensitive proteins make an ionic difference between the inside and the outside of the cells through structural changes, and thus, play a key role in energy production and signaling. Therefore, the photosensitive proteins are utilized in the treatment of incurable diseases, solar cells, photo-catalysts, and the like through structural analysis.
However, the structural change of each protein significantly depends on the wavelength of light, and thus, has a limit thereof. Therefore, it is important to realize artificial evolution through the reconstitution of photosystem II and rhodopsin proteins into cells to extend the operation wavelength ranges of the proteins to the entire range of visible light. This fact can induce a remarkable development in high-efficiency solar cells, photo-catalysts, or medical treatment employing wide wavelength ranges, which could not be applied by existing techniques.
The reconstitution of membrane proteins has already been widely used for various purposes in cell membrane studies and membrane protein-related studies since the insertion into liposomes made of artificial phospholipid molecules has first been known by Kagawa and Racker in 1971 (J. Biol. Chem. 246, 1971, 5477; Int. J. Biochem. 20, 1988, 889).
In addition, conventional inventions and studies merely suggested that a single photosensitive protein is inserted into the cellular membrane to check the state of the protein and reproduce existing phenomena, and thus had a drawback in that only some wavelength ranges of visible light are used.
Moreover, the technology has not yet been presented that maximizes the photosensitivity to light and extends the function of separating ions by reconstituting two or more heterologous proteins into a single phospholipid vesicle.
Accordingly, the present inventors have recognized that, if heterologous proteins can be operated at the same time, the functions of the proteins can be performed at the entire wavelength of visible light, UV light, and even a portion of infrared light.
Throughout the entire specification, many papers and patent documents are referenced and their citations are represented. The disclosures of the cited papers and patent documents are entirely incorporated by reference into the present specification, and the level of the technical field within which the present invention falls and the details of the present invention are thus explained more clearly.